This proposal describes a comprehensive research project designed to study short- and long-term stress and mental health effects of petrochemical disasters. Workers at refineries and petrochemical plants who have been victimized by explosions and fires in their work settings constitute an understudied disaster population. Further, the nature of these disasters, particularly their sudden onset, fiery and immediate threat to life and limb, their human cause, and the fact that the exposure to toxic chemicals and/or fumes are likely during such explosions make them theoretically important and of considerable applied interest. The proposed research expands the range and diversity of stress and health measurements across an extended post-disaster period and permits analysis of acute responses and their impact on chronic outcomes. Retrospective and prospective approaches are proposed. Data relevant to interactions and coping efficacy will be collected, and a small-scale evaluation of a debriefing intervention is proposed to examine secondary prevention efforts in this population. The project is proposed in three studies. The first is a retrospective study of 300 Oil, Chemical, and Atomic Workers Union (OCAW) half of whom were on duty and half of whom were off-duty at the time that disasters occurred between 1989 and 1992. A third group of OCAW members who began working at the sites after the disasters will serve as a control group. Data will be collected at four six-month intervals. The second study will examine the effects of OCAW members at plants experiencing disasters after the beginning of this project. Data will be collected at six points during a two- year period. Participants will include 150 workers who were on duty during the disaster and 180 who were off at the time. A total of six plants will be studied. Workers at three of these plants will receive a debriefing intervention session. Workers at the remaining three plants will receive an informational intervention. Measures include symptom checklists, stress load, measures of negative affect and perceived demand, task performance measures, resting blood pressure and heart rate, urinary catecholamine and cortisol, and self reports of health and illness episodes as well as mediating variables such as gender. These measures will be supplemented by health reports, mental health interview data, and post-traumatic stress disorder measures.